Direct radiative recombination in the Se-terminated nanoscale Si porous structure

► We attain ultrafast recombination lifetimes of 0.49 and 2.68 ns in the Se-treated Si porous structure. ► The fast recombination rate is considered to origin from the direct radiative recombination induced by surface modification. ► Excitation wavelength- and temperature-dependent PL spectra are carried out. ► A near-infrared emission band with wavelength around the optimal energy region of light-transfer in optical fiber is observed. ► PLE spectrum indicates the near-infrared PL band is due to recombination in defect states.